FARGO, N.D. - The Environmental Protection Agency has a short-term registration for a new dicamba formulation - Xtendimax with Vapor Grip Technology - a low-volatility formula that can be applied on genetically engineered dicamba-tolerant soybeans.
North Dakota State University Extension Service Weed Specialist Rich Zollinger says North Dakota, Minnesota and South Dakota are among 34 states where the formula can be used on dicamba-tolerant soybeans. Southern states will also use it on cotton.
Dicamba-resistant soybean was registered in 2016, Zollinger says, and many growers planted dicamba-resistant crops. But the herbicide that goes with it - a form of dicamba - wasn't approved until Nov. 9. Seed companies have developed lines with a better fit for the southern region of the U.S., and is designed to engage what Zollinger calls "rampant weed resistance" to glyphosate and glyphosate-dicamba across the country and North Dakota.
Dicamba has been used in wheat and corn for many years and is very effective weed control, Zollinger says. Now it can be used on soybeans to kill many broadleaf weeds in those fields.
Not fool proof
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"This kind of technology is completely different than anything we've had before," Zollinger says. "Glyphosate doesn't volatilize-doesn't form vapors. Dicamba does. The companies - BASF and Monsanto have formulated the active ingredient in such a way that it will not volatilize as much as the other formulations."
The product is not foolproof and it still can move off-site, Zollinger says. The companies have come out with best management practices. These BMPs dictate lowering boom height, using nozzles that provide large droplets, using the product at low speed, and using several drift mitigating techniques to help prevent water movement. "Dicamba will kill a lot of weeds but it can harm many other plants, such as trees, vegetables, flowers and other broadleaf crops," he says.
Farmers in some southern states have become "desperate" to control herbicide-resistant crops, especially Palmer amaranth weed, which puts out hundreds of thousands of seeds per plant. Some farmers bought the new seeds, but without the chemical registration were "tempted to the point where they actually used the herbicide illegally, and some used formulations that were more volatile, and were probably cheaper," Zollinger says. When the herbicide volatilized, it moved off-target and harmed surrounding crops, vegetables and flowers.
Non-dicamba-resistant soybeans would be most likely to be harmed in North Dakota. A bottle capful of dicamba in a tank will curl the leaves on susceptible crops. Sunflowers, canola and field peas are all susceptible and would show some leaf-cupping and possibly yield loss from volatilized dicamba.
The long wait
Carl Peterson, president of Peterson Farms Seed in Harwood, N.D., says the approval is an important development. The industry has been looking forward to the Xtend technology for three or four years.
The technology will "grab a very significant part of the market share in our region this coming spring," he says. Many companies, including Peterson's, produced significant quantities of seed for the coming year.
Most of the industry has access to the Monsanto-derived technology, but some companies were more aggressive in moving the product into the marketplace. A year ago, when companies were planting the 2016 seed crop, the European Union hadn't approved the beans and elevators weren't accepting Xtend beans, some companies slowed down, while others sped up.
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"The volatility is a big deal because typically a dicamba - Banvel or Clarity formulations of that herbicide - have had a tendency to move in humid and hot conditions," Peterson says. "This new formulation all but eliminates that."
Peterson says there has been herbicide weed resistance since about 1947, but it became more prevalent because farmers overused glyphosate or Roundup. "The Xtend system is another answer," he says, but adds it must be managed to avoid overuse.
The dicamba formulation will no-doubt be mixed with glyphosate (Roundup), a combination which the EPA is expected to approve before planting time. "Most of the corn in the area is Roundup Ready, as well, so you still need a tank mix partner (dicamba) to get rid of the Roundup Ready corn (weeds) in your bean fields," Peterson says.
He says state approval should happen quickly. He doesn't expect stricter rules in North Dakota. Some early proposals were 110- to 220-foot buffer distances, depending on rates used, for spraying next to crops that are sensitive to dicamba. The reality is that farmers will likely be more careful than the law requires, Peterson says, spot-spraying next to downwind neighbors growing sugar beets or other sensitive crops.
State process
Jerry Sauter, pesticide program manager for the North Dakota Department of Agriculture, says the department hadn't yet received the permit application request as of Nov. 14, but says he expects the application will come when it needs to. The department would make sure the application is complete, suggest any desired changes, and then either approve or deny it. That's usually done within a month, unless there are changes.
Sauter says the department "is discussing" whether they need to propose additional restrictions on the formulation. "There's a lot of discussion around it with all of the misuse and the EPA only giving it a short-term registration," he says. "Nothing has been seriously proposed."
The formulation contains an additive that reduces its volatility, or evaporation. It is different from products that were alleged to have been used illegally, which the EPA continues to investigate in various parts of the Midwest.
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The label requires drift mitigation measures. They include: no application from aircraft; no application when wind speed is over 15 mph; application only with approved nozzles at specific pressures; and buffer zones to protect sensitive areas when the wind is blowing toward them. It includes reporting by the registrant to EPA of any suspected resistance as well as remediation and grower education. The EPA is placing time limits on the registration to allow the agency to either let the registration expire or make it easy to make necessary changes if there are problems with resistant weeds or pesticide drift.
